The isolation and purification of esterase 1 from the cystosol of rabbit neutrophils will be further pursued using preparative iso-electric focusing. Attempts will be made to obtain antibody to esterase 1. An attempt will be made to demonstrate histochemically the site in the neutrophil of pro-esterase 1 using indoxyl acetate as a substrate. The effect of chemotactic factors on K ion, Na ion and Ca2 ion transport in rabbit neutrophils will be further pursued and the relation of these changes will be explored in collaboration with Dr. Ramadan Sha'afi and his associates of this institution. The structure activity relationships of simple oligopeptides as chemotactic agents, lysosomal enzyme inducers and enhancers of phagocytosis will be further explored. We will attempt to delineate the nature of the esterase activated when anti-mouse anti-Ig reacts with mouse B lymphocytes using trypsin substrates and assays of increased sensitivity. This will be done in collaboration with Dr. Emil Unanue of Harvard. BIBLIOGRAPHIC REFERENCES: Showell, H.J. and Becker, E.L.: The effects of external K ion and Na ion on the chemotaxis of rabbit peritoneal neutrophils. J. Immunol. 116:99-105, 1976. Showell, J.H., Freer, R.J., Zigmond, S.H., Schiffmann, E., Answanikumar, S., Corcoran, B. and Becker, E.L.: The structure-activity relations of synthetic peptides as chemotactic factors and inducers of lysosomal enzyme secretion for neutrophils. J. Exp. Med. 143:1154-1169, 1976.